package tree;

public class 对称二叉树101 {

    //1.递归
    public boolean isSymmetric(TreeNode root) {
        return isMirror(root, root);
    }

    public boolean isMirror(TreeNode t1, TreeNode t2) {
        if (t1 == null && t2 == null) {
            return true;
        }
        if (t1 == null || t2 == null) {
            return false;
        }
        return (t1.val == t2.val) && isMirror(t1.right, t2.left) && isMirror(t1.left, t2.right);
    }
}
